/* ----------------------------------------------------------------------
* Copyright (C) 2010-2014 ARM Limited. All rights reserved.
*
* $Date:        19. March 2015
* $Revision: 	V.1.4.5
*
* Project: 	    CMSIS DSP Library
* Title:	    arm_fir_f32.c
*
* Description:	Floating-point FIR filter processing function.
*
* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*   - Redistributions of source code must retain the above copyright
*     notice, this list of conditions and the following disclaimer.
*   - Redistributions in binary form must reproduce the above copyright
*     notice, this list of conditions and the following disclaimer in
*     the documentation and/or other materials provided with the
*     distribution.
*   - Neither the name of ARM LIMITED nor the names of its contributors
*     may be used to endorse or promote products derived from this
*     software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
* -------------------------------------------------------------------- */

#include "arm_math.h"

/**
* @ingroup groupFilters
*/

/**
* @defgroup FIR Finite Impulse Response (FIR) Filters
*
* This set of functions implements Finite Impulse Response (FIR) filters
* for Q7, Q15, Q31, and floating-point data types.  Fast versions of Q15 and Q31 are also provided.
* The functions operate on blocks of input and output data and each call to the function processes
* <code>blockSize</code> samples through the filter.  <code>pSrc</code> and
* <code>pDst</code> points to input and output arrays containing <code>blockSize</code> values.
*
* \par Algorithm:
* The FIR filter algorithm is based upon a sequence of multiply-accumulate (MAC) operations.
* Each filter coefficient <code>b[n]</code> is multiplied by a state variable which equals a previous input sample <code>x[n]</code>.
* <pre>
*    y[n] = b[0] * x[n] + b[1] * x[n-1] + b[2] * x[n-2] + ...+ b[numTaps-1] * x[n-numTaps+1]
* </pre>
* \par
* \image html FIR.gif "Finite Impulse Response filter"
* \par
* <code>pCoeffs</code> points to a coefficient array of size <code>numTaps</code>.
* Coefficients are stored in time reversed order.
* \par
* <pre>
*    {b[numTaps-1], b[numTaps-2], b[N-2], ..., b[1], b[0]}
* </pre>
* \par
* <code>pState</code> points to a state array of size <code>numTaps + blockSize - 1</code>.
* Samples in the state buffer are stored in the following order.
* \par
* <pre>
*    {x[n-numTaps+1], x[n-numTaps], x[n-numTaps-1], x[n-numTaps-2]....x[0], x[1], ..., x[blockSize-1]}
* </pre>
* \par
* Note that the length of the state buffer exceeds the length of the coefficient array by <code>blockSize-1</code>.
* The increased state buffer length allows circular addressing, which is traditionally used in the FIR filters,
* to be avoided and yields a significant speed improvement.
* The state variables are updated after each block of data is processed; the coefficients are untouched.
* \par Instance Structure
* The coefficients and state variables for a filter are stored together in an instance data structure.
* A separate instance structure must be defined for each filter.
* Coefficient arrays may be shared among several instances while state variable arrays cannot be shared.
* There are separate instance structure declarations for each of the 4 supported data types.
*
* \par Initialization Functions
* There is also an associated initialization function for each data type.
* The initialization function performs the following operations:
* - Sets the values of the internal structure fields.
* - Zeros out the values in the state buffer.
* To do this manually without calling the init function, assign the follow subfields of the instance structure:
* numTaps, pCoeffs, pState. Also set all of the values in pState to zero.
*
* \par
* Use of the initialization function is optional.
* However, if the initialization function is used, then the instance structure cannot be placed into a const data section.
* To place an instance structure into a const data section, the instance structure must be manually initialized.
* Set the values in the state buffer to zeros before static initialization.
* The code below statically initializes each of the 4 different data type filter instance structures
* <pre>
*arm_fir_instance_f32 S = {numTaps, pState, pCoeffs};
*arm_fir_instance_q31 S = {numTaps, pState, pCoeffs};
*arm_fir_instance_q15 S = {numTaps, pState, pCoeffs};
*arm_fir_instance_q7 S =  {numTaps, pState, pCoeffs};
* </pre>
*
* where <code>numTaps</code> is the number of filter coefficients in the filter; <code>pState</code> is the address of the state buffer;
* <code>pCoeffs</code> is the address of the coefficient buffer.
*
* \par Fixed-Point Behavior
* Care must be taken when using the fixed-point versions of the FIR filter functions.
* In particular, the overflow and saturation behavior of the accumulator used in each function must be considered.
* Refer to the function specific documentation below for usage guidelines.
*/

/**
* @addtogroup FIR
* @{
*/

/**
*
* @param[in]  *S points to an instance of the floating-point FIR filter structure.
* @param[in]  *pSrc points to the block of input data.
* @param[out] *pDst points to the block of output data.
* @param[in]  blockSize number of samples to process per call.
* @return     none.
*
*/

#if defined(ARM_MATH_CM7)

void arm_fir_f32(
    const arm_fir_instance_f32 *S,
    float32_t *pSrc,
    float32_t *pDst,
    uint32_t blockSize)
{
    float32_t *pState = S->pState;                 /* State pointer */
    float32_t *pCoeffs = S->pCoeffs;               /* Coefficient pointer */
    float32_t *pStateCurnt;                        /* Points to the current sample of the state */
    float32_t *px, *pb;                            /* Temporary pointers for state and coefficient buffers */
    float32_t acc0, acc1, acc2, acc3, acc4, acc5, acc6, acc7;     /* Accumulators */
    float32_t x0, x1, x2, x3, x4, x5, x6, x7, c0;  /* Temporary variables to hold state and coefficient values */
    uint32_t numTaps = S->numTaps;                 /* Number of filter coefficients in the filter */
    uint32_t i, tapCnt, blkCnt;                    /* Loop counters */

    /* S->pState points to state array which contains previous frame (numTaps - 1) samples */
    /* pStateCurnt points to the location where the new input data should be written */
    pStateCurnt = &(S->pState[(numTaps - 1u)]);

    /* Apply loop unrolling and compute 8 output values simultaneously.
     * The variables acc0 ... acc7 hold output values that are being computed:
     *
     *    acc0 =  b[numTaps-1] * x[n-numTaps-1] + b[numTaps-2] * x[n-numTaps-2] + b[numTaps-3] * x[n-numTaps-3] +...+ b[0] * x[0]
     *    acc1 =  b[numTaps-1] * x[n-numTaps] +   b[numTaps-2] * x[n-numTaps-1] + b[numTaps-3] * x[n-numTaps-2] +...+ b[0] * x[1]
     *    acc2 =  b[numTaps-1] * x[n-numTaps+1] + b[numTaps-2] * x[n-numTaps] +   b[numTaps-3] * x[n-numTaps-1] +...+ b[0] * x[2]
     *    acc3 =  b[numTaps-1] * x[n-numTaps+2] + b[numTaps-2] * x[n-numTaps+1] + b[numTaps-3] * x[n-numTaps]   +...+ b[0] * x[3]
     */
    blkCnt = blockSize >> 3;

    /* First part of the processing with loop unrolling.  Compute 8 outputs at a time.
    ** a second loop below computes the remaining 1 to 7 samples. */
    while(blkCnt > 0u)
    {
        /* Copy four new input samples into the state buffer */
        *pStateCurnt++ = *pSrc++;
        *pStateCurnt++ = *pSrc++;
        *pStateCurnt++ = *pSrc++;
        *pStateCurnt++ = *pSrc++;

        /* Set all accumulators to zero */
        acc0 = 0.0f;
        acc1 = 0.0f;
        acc2 = 0.0f;
        acc3 = 0.0f;
        acc4 = 0.0f;
        acc5 = 0.0f;
        acc6 = 0.0f;
        acc7 = 0.0f;

        /* Initialize state pointer */
        px = pState;

        /* Initialize coeff pointer */
        pb = (pCoeffs);

        /* This is separated from the others to avoid
         * a call to __aeabi_memmove which would be slower
         */
        *pStateCurnt++ = *pSrc++;
        *pStateCurnt++ = *pSrc++;
        *pStateCurnt++ = *pSrc++;
        *pStateCurnt++ = *pSrc++;

        /* Read the first seven samples from the state buffer:  x[n-numTaps], x[n-numTaps-1], x[n-numTaps-2] */
        x0 = *px++;
        x1 = *px++;
        x2 = *px++;
        x3 = *px++;
        x4 = *px++;
        x5 = *px++;
        x6 = *px++;

        /* Loop unrolling.  Process 8 taps at a time. */
        tapCnt = numTaps >> 3u;

        /* Loop over the number of taps.  Unroll by a factor of 8.
         ** Repeat until we've computed numTaps-8 coefficients. */
        while(tapCnt > 0u)
        {
            /* Read the b[numTaps-1] coefficient */
            c0 = *(pb++);

            /* Read x[n-numTaps-3] sample */
            x7 = *(px++);

            /* acc0 +=  b[numTaps-1] * x[n-numTaps] */
            acc0 += x0 * c0;

            /* acc1 +=  b[numTaps-1] * x[n-numTaps-1] */
            acc1 += x1 * c0;

            /* acc2 +=  b[numTaps-1] * x[n-numTaps-2] */
            acc2 += x2 * c0;

            /* acc3 +=  b[numTaps-1] * x[n-numTaps-3] */
            acc3 += x3 * c0;

            /* acc4 +=  b[numTaps-1] * x[n-numTaps-4] */
            acc4 += x4 * c0;

            /* acc1 +=  b[numTaps-1] * x[n-numTaps-5] */
            acc5 += x5 * c0;

            /* acc2 +=  b[numTaps-1] * x[n-numTaps-6] */
            acc6 += x6 * c0;

            /* acc3 +=  b[numTaps-1] * x[n-numTaps-7] */
            acc7 += x7 * c0;

            /* Read the b[numTaps-2] coefficient */
            c0 = *(pb++);

            /* Read x[n-numTaps-4] sample */
            x0 = *(px++);

            /* Perform the multiply-accumulate */
            acc0 += x1 * c0;
            acc1 += x2 * c0;
            acc2 += x3 * c0;
            acc3 += x4 * c0;
            acc4 += x5 * c0;
            acc5 += x6 * c0;
            acc6 += x7 * c0;
            acc7 += x0 * c0;

            /* Read the b[numTaps-3] coefficient */
            c0 = *(pb++);

            /* Read x[n-numTaps-5] sample */
            x1 = *(px++);

            /* Perform the multiply-accumulates */
            acc0 += x2 * c0;
            acc1 += x3 * c0;
            acc2 += x4 * c0;
            acc3 += x5 * c0;
            acc4 += x6 * c0;
            acc5 += x7 * c0;
            acc6 += x0 * c0;
            acc7 += x1 * c0;

            /* Read the b[numTaps-4] coefficient */
            c0 = *(pb++);

            /* Read x[n-numTaps-6] sample */
            x2 = *(px++);

            /* Perform the multiply-accumulates */
            acc0 += x3 * c0;
            acc1 += x4 * c0;
            acc2 += x5 * c0;
            acc3 += x6 * c0;
            acc4 += x7 * c0;
            acc5 += x0 * c0;
            acc6 += x1 * c0;
            acc7 += x2 * c0;

            /* Read the b[numTaps-4] coefficient */
            c0 = *(pb++);

            /* Read x[n-numTaps-6] sample */
            x3 = *(px++);
            /* Perform the multiply-accumulates */
            acc0 += x4 * c0;
            acc1 += x5 * c0;
            acc2 += x6 * c0;
            acc3 += x7 * c0;
            acc4 += x0 * c0;
            acc5 += x1 * c0;
            acc6 += x2 * c0;
            acc7 += x3 * c0;

            /* Read the b[numTaps-4] coefficient */
            c0 = *(pb++);

            /* Read x[n-numTaps-6] sample */
            x4 = *(px++);

            /* Perform the multiply-accumulates */
            acc0 += x5 * c0;
            acc1 += x6 * c0;
            acc2 += x7 * c0;
            acc3 += x0 * c0;
            acc4 += x1 * c0;
            acc5 += x2 * c0;
            acc6 += x3 * c0;
            acc7 += x4 * c0;

            /* Read the b[numTaps-4] coefficient */
            c0 = *(pb++);

            /* Read x[n-numTaps-6] sample */
            x5 = *(px++);

            /* Perform the multiply-accumulates */
            acc0 += x6 * c0;
            acc1 += x7 * c0;
            acc2 += x0 * c0;
            acc3 += x1 * c0;
            acc4 += x2 * c0;
            acc5 += x3 * c0;
            acc6 += x4 * c0;
            acc7 += x5 * c0;

            /* Read the b[numTaps-4] coefficient */
            c0 = *(pb++);

            /* Read x[n-numTaps-6] sample */
            x6 = *(px++);

            /* Perform the multiply-accumulates */
            acc0 += x7 * c0;
            acc1 += x0 * c0;
            acc2 += x1 * c0;
            acc3 += x2 * c0;
            acc4 += x3 * c0;
            acc5 += x4 * c0;
            acc6 += x5 * c0;
            acc7 += x6 * c0;

            tapCnt--;
        }

        /* If the filter length is not a multiple of 8, compute the remaining filter taps */
        tapCnt = numTaps % 0x8u;

        while(tapCnt > 0u)
        {
            /* Read coefficients */
            c0 = *(pb++);

            /* Fetch 1 state variable */
            x7 = *(px++);

            /* Perform the multiply-accumulates */
            acc0 += x0 * c0;
            acc1 += x1 * c0;
            acc2 += x2 * c0;
            acc3 += x3 * c0;
            acc4 += x4 * c0;
            acc5 += x5 * c0;
            acc6 += x6 * c0;
            acc7 += x7 * c0;

            /* Reuse the present sample states for next sample */
            x0 = x1;
            x1 = x2;
            x2 = x3;
            x3 = x4;
            x4 = x5;
            x5 = x6;
            x6 = x7;

            /* Decrement the loop counter */
            tapCnt--;
        }

        /* Advance the state pointer by 8 to process the next group of 8 samples */
        pState = pState + 8;

        /* The results in the 8 accumulators, store in the destination buffer. */
        *pDst++ = acc0;
        *pDst++ = acc1;
        *pDst++ = acc2;
        *pDst++ = acc3;
        *pDst++ = acc4;
        *pDst++ = acc5;
        *pDst++ = acc6;
        *pDst++ = acc7;

        blkCnt--;
    }

    /* If the blockSize is not a multiple of 8, compute any remaining output samples here.
    ** No loop unrolling is used. */
    blkCnt = blockSize % 0x8u;

    while(blkCnt > 0u)
    {
        /* Copy one sample at a time into state buffer */
        *pStateCurnt++ = *pSrc++;

        /* Set the accumulator to zero */
        acc0 = 0.0f;

        /* Initialize state pointer */
        px = pState;

        /* Initialize Coefficient pointer */
        pb = (pCoeffs);

        i = numTaps;

        /* Perform the multiply-accumulates */
        do
        {
            acc0 += *px++ * *pb++;
            i--;

        }
        while(i > 0u);

        /* The result is store in the destination buffer. */
        *pDst++ = acc0;

        /* Advance state pointer by 1 for the next sample */
        pState = pState + 1;

        blkCnt--;
    }

    /* Processing is complete.
    ** Now copy the last numTaps - 1 samples to the start of the state buffer.
    ** This prepares the state buffer for the next function call. */

    /* Points to the start of the state buffer */
    pStateCurnt = S->pState;

    tapCnt = (numTaps - 1u) >> 2u;

    /* copy data */
    while(tapCnt > 0u)
    {
        *pStateCurnt++ = *pState++;
        *pStateCurnt++ = *pState++;
        *pStateCurnt++ = *pState++;
        *pStateCurnt++ = *pState++;

        /* Decrement the loop counter */
        tapCnt--;
    }

    /* Calculate remaining number of copies */
    tapCnt = (numTaps - 1u) % 0x4u;

    /* Copy the remaining q31_t data */
    while(tapCnt > 0u)
    {
        *pStateCurnt++ = *pState++;

        /* Decrement the loop counter */
        tapCnt--;
    }
}

#elif defined(ARM_MATH_CM0_FAMILY)

void arm_fir_f32(
    const arm_fir_instance_f32 *S,
    float32_t *pSrc,
    float32_t *pDst,
    uint32_t blockSize)
{
    float32_t *pState = S->pState;                 /* State pointer */
    float32_t *pCoeffs = S->pCoeffs;               /* Coefficient pointer */
    float32_t *pStateCurnt;                        /* Points to the current sample of the state */
    float32_t *px, *pb;                            /* Temporary pointers for state and coefficient buffers */
    uint32_t numTaps = S->numTaps;                 /* Number of filter coefficients in the filter */
    uint32_t i, tapCnt, blkCnt;                    /* Loop counters */

    /* Run the below code for Cortex-M0 */

    float32_t acc;

    /* S->pState points to state array which contains previous frame (numTaps - 1) samples */
    /* pStateCurnt points to the location where the new input data should be written */
    pStateCurnt = &(S->pState[(numTaps - 1u)]);

    /* Initialize blkCnt with blockSize */
    blkCnt = blockSize;

    while(blkCnt > 0u)
    {
        /* Copy one sample at a time into state buffer */
        *pStateCurnt++ = *pSrc++;

        /* Set the accumulator to zero */
        acc = 0.0f;

        /* Initialize state pointer */
        px = pState;

        /* Initialize Coefficient pointer */
        pb = pCoeffs;

        i = numTaps;

        /* Perform the multiply-accumulates */
        do
        {
            /* acc =  b[numTaps-1] * x[n-numTaps-1] + b[numTaps-2] * x[n-numTaps-2] + b[numTaps-3] * x[n-numTaps-3] +...+ b[0] * x[0] */
            acc += *px++ * *pb++;
            i--;

        }
        while(i > 0u);

        /* The result is store in the destination buffer. */
        *pDst++ = acc;

        /* Advance state pointer by 1 for the next sample */
        pState = pState + 1;

        blkCnt--;
    }

    /* Processing is complete.
    ** Now copy the last numTaps - 1 samples to the starting of the state buffer.
    ** This prepares the state buffer for the next function call. */

    /* Points to the start of the state buffer */
    pStateCurnt = S->pState;

    /* Copy numTaps number of values */
    tapCnt = numTaps - 1u;

    /* Copy data */
    while(tapCnt > 0u)
    {
        *pStateCurnt++ = *pState++;

        /* Decrement the loop counter */
        tapCnt--;
    }

}

#else

/* Run the below code for Cortex-M4 and Cortex-M3 */

void arm_fir_f32(
    const arm_fir_instance_f32 *S,
    float32_t *pSrc,
    float32_t *pDst,
    uint32_t blockSize)
{
    float32_t *pState = S->pState;                 /* State pointer */
    float32_t *pCoeffs = S->pCoeffs;               /* Coefficient pointer */
    float32_t *pStateCurnt;                        /* Points to the current sample of the state */
    float32_t *px, *pb;                            /* Temporary pointers for state and coefficient buffers */
    float32_t acc0, acc1, acc2, acc3, acc4, acc5, acc6, acc7;     /* Accumulators */
    float32_t x0, x1, x2, x3, x4, x5, x6, x7, c0;  /* Temporary variables to hold state and coefficient values */
    uint32_t numTaps = S->numTaps;                 /* Number of filter coefficients in the filter */
    uint32_t i, tapCnt, blkCnt;                    /* Loop counters */
    float32_t p0, p1, p2, p3, p4, p5, p6, p7;      /* Temporary product values */

    /* S->pState points to state array which contains previous frame (numTaps - 1) samples */
    /* pStateCurnt points to the location where the new input data should be written */
    pStateCurnt = &(S->pState[(numTaps - 1u)]);

    /* Apply loop unrolling and compute 8 output values simultaneously.
     * The variables acc0 ... acc7 hold output values that are being computed:
     *
     *    acc0 =  b[numTaps-1] * x[n-numTaps-1] + b[numTaps-2] * x[n-numTaps-2] + b[numTaps-3] * x[n-numTaps-3] +...+ b[0] * x[0]
     *    acc1 =  b[numTaps-1] * x[n-numTaps] +   b[numTaps-2] * x[n-numTaps-1] + b[numTaps-3] * x[n-numTaps-2] +...+ b[0] * x[1]
     *    acc2 =  b[numTaps-1] * x[n-numTaps+1] + b[numTaps-2] * x[n-numTaps] +   b[numTaps-3] * x[n-numTaps-1] +...+ b[0] * x[2]
     *    acc3 =  b[numTaps-1] * x[n-numTaps+2] + b[numTaps-2] * x[n-numTaps+1] + b[numTaps-3] * x[n-numTaps]   +...+ b[0] * x[3]
     */
    blkCnt = blockSize >> 3;

    /* First part of the processing with loop unrolling.  Compute 8 outputs at a time.
    ** a second loop below computes the remaining 1 to 7 samples. */
    while(blkCnt > 0u)
    {
        /* Copy four new input samples into the state buffer */
        *pStateCurnt++ = *pSrc++;
        *pStateCurnt++ = *pSrc++;
        *pStateCurnt++ = *pSrc++;
        *pStateCurnt++ = *pSrc++;

        /* Set all accumulators to zero */
        acc0 = 0.0f;
        acc1 = 0.0f;
        acc2 = 0.0f;
        acc3 = 0.0f;
        acc4 = 0.0f;
        acc5 = 0.0f;
        acc6 = 0.0f;
        acc7 = 0.0f;

        /* Initialize state pointer */
        px = pState;

        /* Initialize coeff pointer */
        pb = (pCoeffs);

        /* This is separated from the others to avoid
         * a call to __aeabi_memmove which would be slower
         */
        *pStateCurnt++ = *pSrc++;
        *pStateCurnt++ = *pSrc++;
        *pStateCurnt++ = *pSrc++;
        *pStateCurnt++ = *pSrc++;

        /* Read the first seven samples from the state buffer:  x[n-numTaps], x[n-numTaps-1], x[n-numTaps-2] */
        x0 = *px++;
        x1 = *px++;
        x2 = *px++;
        x3 = *px++;
        x4 = *px++;
        x5 = *px++;
        x6 = *px++;

        /* Loop unrolling.  Process 8 taps at a time. */
        tapCnt = numTaps >> 3u;

        /* Loop over the number of taps.  Unroll by a factor of 8.
         ** Repeat until we've computed numTaps-8 coefficients. */
        while(tapCnt > 0u)
        {
            /* Read the b[numTaps-1] coefficient */
            c0 = *(pb++);

            /* Read x[n-numTaps-3] sample */
            x7 = *(px++);

            /* acc0 +=  b[numTaps-1] * x[n-numTaps] */
            p0 = x0 * c0;

            /* acc1 +=  b[numTaps-1] * x[n-numTaps-1] */
            p1 = x1 * c0;

            /* acc2 +=  b[numTaps-1] * x[n-numTaps-2] */
            p2 = x2 * c0;

            /* acc3 +=  b[numTaps-1] * x[n-numTaps-3] */
            p3 = x3 * c0;

            /* acc4 +=  b[numTaps-1] * x[n-numTaps-4] */
            p4 = x4 * c0;

            /* acc1 +=  b[numTaps-1] * x[n-numTaps-5] */
            p5 = x5 * c0;

            /* acc2 +=  b[numTaps-1] * x[n-numTaps-6] */
            p6 = x6 * c0;

            /* acc3 +=  b[numTaps-1] * x[n-numTaps-7] */
            p7 = x7 * c0;

            /* Read the b[numTaps-2] coefficient */
            c0 = *(pb++);

            /* Read x[n-numTaps-4] sample */
            x0 = *(px++);

            acc0 += p0;
            acc1 += p1;
            acc2 += p2;
            acc3 += p3;
            acc4 += p4;
            acc5 += p5;
            acc6 += p6;
            acc7 += p7;


            /* Perform the multiply-accumulate */
            p0 = x1 * c0;
            p1 = x2 * c0;
            p2 = x3 * c0;
            p3 = x4 * c0;
            p4 = x5 * c0;
            p5 = x6 * c0;
            p6 = x7 * c0;
            p7 = x0 * c0;

            /* Read the b[numTaps-3] coefficient */
            c0 = *(pb++);

            /* Read x[n-numTaps-5] sample */
            x1 = *(px++);

            acc0 += p0;
            acc1 += p1;
            acc2 += p2;
            acc3 += p3;
            acc4 += p4;
            acc5 += p5;
            acc6 += p6;
            acc7 += p7;

            /* Perform the multiply-accumulates */
            p0 = x2 * c0;
            p1 = x3 * c0;
            p2 = x4 * c0;
            p3 = x5 * c0;
            p4 = x6 * c0;
            p5 = x7 * c0;
            p6 = x0 * c0;
            p7 = x1 * c0;

            /* Read the b[numTaps-4] coefficient */
            c0 = *(pb++);

            /* Read x[n-numTaps-6] sample */
            x2 = *(px++);

            acc0 += p0;
            acc1 += p1;
            acc2 += p2;
            acc3 += p3;
            acc4 += p4;
            acc5 += p5;
            acc6 += p6;
            acc7 += p7;

            /* Perform the multiply-accumulates */
            p0 = x3 * c0;
            p1 = x4 * c0;
            p2 = x5 * c0;
            p3 = x6 * c0;
            p4 = x7 * c0;
            p5 = x0 * c0;
            p6 = x1 * c0;
            p7 = x2 * c0;

            /* Read the b[numTaps-4] coefficient */
            c0 = *(pb++);

            /* Read x[n-numTaps-6] sample */
            x3 = *(px++);

            acc0 += p0;
            acc1 += p1;
            acc2 += p2;
            acc3 += p3;
            acc4 += p4;
            acc5 += p5;
            acc6 += p6;
            acc7 += p7;

            /* Perform the multiply-accumulates */
            p0 = x4 * c0;
            p1 = x5 * c0;
            p2 = x6 * c0;
            p3 = x7 * c0;
            p4 = x0 * c0;
            p5 = x1 * c0;
            p6 = x2 * c0;
            p7 = x3 * c0;

            /* Read the b[numTaps-4] coefficient */
            c0 = *(pb++);

            /* Read x[n-numTaps-6] sample */
            x4 = *(px++);

            acc0 += p0;
            acc1 += p1;
            acc2 += p2;
            acc3 += p3;
            acc4 += p4;
            acc5 += p5;
            acc6 += p6;
            acc7 += p7;

            /* Perform the multiply-accumulates */
            p0 = x5 * c0;
            p1 = x6 * c0;
            p2 = x7 * c0;
            p3 = x0 * c0;
            p4 = x1 * c0;
            p5 = x2 * c0;
            p6 = x3 * c0;
            p7 = x4 * c0;

            /* Read the b[numTaps-4] coefficient */
            c0 = *(pb++);

            /* Read x[n-numTaps-6] sample */
            x5 = *(px++);

            acc0 += p0;
            acc1 += p1;
            acc2 += p2;
            acc3 += p3;
            acc4 += p4;
            acc5 += p5;
            acc6 += p6;
            acc7 += p7;

            /* Perform the multiply-accumulates */
            p0 = x6 * c0;
            p1 = x7 * c0;
            p2 = x0 * c0;
            p3 = x1 * c0;
            p4 = x2 * c0;
            p5 = x3 * c0;
            p6 = x4 * c0;
            p7 = x5 * c0;

            /* Read the b[numTaps-4] coefficient */
            c0 = *(pb++);

            /* Read x[n-numTaps-6] sample */
            x6 = *(px++);

            acc0 += p0;
            acc1 += p1;
            acc2 += p2;
            acc3 += p3;
            acc4 += p4;
            acc5 += p5;
            acc6 += p6;
            acc7 += p7;

            /* Perform the multiply-accumulates */
            p0 = x7 * c0;
            p1 = x0 * c0;
            p2 = x1 * c0;
            p3 = x2 * c0;
            p4 = x3 * c0;
            p5 = x4 * c0;
            p6 = x5 * c0;
            p7 = x6 * c0;

            tapCnt--;

            acc0 += p0;
            acc1 += p1;
            acc2 += p2;
            acc3 += p3;
            acc4 += p4;
            acc5 += p5;
            acc6 += p6;
            acc7 += p7;
        }

        /* If the filter length is not a multiple of 8, compute the remaining filter taps */
        tapCnt = numTaps % 0x8u;

        while(tapCnt > 0u)
        {
            /* Read coefficients */
            c0 = *(pb++);

            /* Fetch 1 state variable */
            x7 = *(px++);

            /* Perform the multiply-accumulates */
            p0 = x0 * c0;
            p1 = x1 * c0;
            p2 = x2 * c0;
            p3 = x3 * c0;
            p4 = x4 * c0;
            p5 = x5 * c0;
            p6 = x6 * c0;
            p7 = x7 * c0;

            /* Reuse the present sample states for next sample */
            x0 = x1;
            x1 = x2;
            x2 = x3;
            x3 = x4;
            x4 = x5;
            x5 = x6;
            x6 = x7;

            acc0 += p0;
            acc1 += p1;
            acc2 += p2;
            acc3 += p3;
            acc4 += p4;
            acc5 += p5;
            acc6 += p6;
            acc7 += p7;

            /* Decrement the loop counter */
            tapCnt--;
        }

        /* Advance the state pointer by 8 to process the next group of 8 samples */
        pState = pState + 8;

        /* The results in the 8 accumulators, store in the destination buffer. */
        *pDst++ = acc0;
        *pDst++ = acc1;
        *pDst++ = acc2;
        *pDst++ = acc3;
        *pDst++ = acc4;
        *pDst++ = acc5;
        *pDst++ = acc6;
        *pDst++ = acc7;

        blkCnt--;
    }

    /* If the blockSize is not a multiple of 8, compute any remaining output samples here.
    ** No loop unrolling is used. */
    blkCnt = blockSize % 0x8u;

    while(blkCnt > 0u)
    {
        /* Copy one sample at a time into state buffer */
        *pStateCurnt++ = *pSrc++;

        /* Set the accumulator to zero */
        acc0 = 0.0f;

        /* Initialize state pointer */
        px = pState;

        /* Initialize Coefficient pointer */
        pb = (pCoeffs);

        i = numTaps;

        /* Perform the multiply-accumulates */
        do
        {
            acc0 += *px++ * *pb++;
            i--;

        }
        while(i > 0u);

        /* The result is store in the destination buffer. */
        *pDst++ = acc0;

        /* Advance state pointer by 1 for the next sample */
        pState = pState + 1;

        blkCnt--;
    }

    /* Processing is complete.
    ** Now copy the last numTaps - 1 samples to the start of the state buffer.
    ** This prepares the state buffer for the next function call. */

    /* Points to the start of the state buffer */
    pStateCurnt = S->pState;

    tapCnt = (numTaps - 1u) >> 2u;

    /* copy data */
    while(tapCnt > 0u)
    {
        *pStateCurnt++ = *pState++;
        *pStateCurnt++ = *pState++;
        *pStateCurnt++ = *pState++;
        *pStateCurnt++ = *pState++;

        /* Decrement the loop counter */
        tapCnt--;
    }

    /* Calculate remaining number of copies */
    tapCnt = (numTaps - 1u) % 0x4u;

    /* Copy the remaining q31_t data */
    while(tapCnt > 0u)
    {
        *pStateCurnt++ = *pState++;

        /* Decrement the loop counter */
        tapCnt--;
    }
}

#endif

/**
* @} end of FIR group
*/
